半干旱土添加有机改良剂后有机质的化学结构变化

A 9-month incubation experiment using composted and non-composted amendments derived from vine pruning waste and sewage sludge was carried out to study the effects of the nature and stability of organic amendments on the structural composition of organic matter (OM) in a semi-arid soil.The changes of soil OM,both in the whole soil and in the extractable carbon with pyrophosphate,were evaluated by pyrolysis-gas chromatography and chemical analyses.By the end of the experiment,the soils amended with pruning waste exhibited less organic carbon loss than those receiving sewage sludge.The non-composted residues increased the aliphatic-pyrolytic products of the OM,both in the whole soil and also in the pyrophosphate extract,with the products derived from peptides and proteins being significantly higher.After 9 months,in the soils amended with pruning waste the relative abundance of phenolic-pyrolytic products derived from phenolic compounds,lignin and proteins in the whole soil tended to increase more than those in the soils amended with sewage sludge.However,the extractable OM with pyrophosphate in the soils amended with composted residues tended to have higher contents of these phenolic-pyrolytic products than that in non-composted ones.Thus,despite the stability of pruning waste,the composting of this material promoted the incorporation of phenolic compounds to the soil OM.The pyrolytic indices (furfural/pyrrole and aliphatic/aromatic ratios) showed the diminution of aliphatic compounds and the increase of aromatic compounds,indicating the stabilization of the OM in the amended soils after 9 months.In conclusion,the changes of soil OM depend on the nature and stability of the organic amendments,with composted vine pruning waste favouring humification.     

改良QuEChERS方法结合气相色谱测定红甜菜中20种农药残留

建立了改良的QuEChERS法结合气相色谱-电子捕获检测器用于红甜菜中20种农药残留的联合测定方法。样品中农药残留以乙腈作为提取溶剂,多壁碳纳米管分散固相萃取去除杂质,过滤后经RTX-1色谱柱分离,GC-ECD检测,外标法定量。探讨了气相色谱的程序升温条件,考察了不同提取溶剂及不同的净化方法对检测结果的影响。结果表明：在优化的色谱条件下,20种农药在0.01~0.50 mg/L（莠去津为0.03~0.50 mg/L）范围内线性关系良好,相关系数(R²)均大于0.99,并且得到很好的分离;乙腈与样品的比例为1:2,多壁碳纳米管用量为10 mg的前处理条件下,红甜菜样品在3个浓度的平均回收率为62.0%~116.5%之间,相对标准偏差为1.9%~10.9%,检出限为0.12 µg/L~0.063 mg/L,定量限为0.4 µg/L~0.21 mg/L。该方法操作简单、快速、准确,适用于红甜菜中有机氯及拟除虫菊酯类多农药残留的检测。     

果蔗中百菌清残留特征研究

为了能安全、有效地使用百菌清,了解百菌清在堆储果蔗中的残留变化,以黄皮果蔗为试材,开展不同浓度百菌清在果蔗上的残留检测.参照NY/T 761—2008中的方法,使用75％百菌清可湿性粉剂配制100～500倍液,分别喷洒在堆储果蔗上,每3 d取1次样榨取果蔗汁,测定果蔗中的百菌清含量.结果表明:百菌清的加标平均回收率为100％～103％,RSD值为0.24％～1.71％;在堆储的39 d中,百菌清在果蔗汁中最高残留量为1.24 mg/kg,最低含量为0.07 mg/kg;采用气相色谱测定百菌清含量方法易操作,重复性好,灵敏度高,完全适用于本试验中百菌清的检测.     

分子印迹分散固相萃取-液相色谱串联质谱法测定尿液中克仑特罗

为了快速检测尿液中的痕量克仑特罗,以克仑特罗分子印迹聚合物为吸附剂,建立了基于分子印迹的分散固相萃取液质联用测定尿液中克仑特罗检测方法。样品用分子印迹聚合物吸附,甲醇/乙酸/水(7/2/1)洗脱,氮气吹干后用0.1%甲酸水/甲醇(9/1)溶液定容,过0.22 μm滤膜后可进行LC-MS/MS分析。结果表明,分子印迹聚合物对克仑特罗有良好的结合性,在0.2~25 μg/L质量溶液范围内有良好的线性关系(r=0.9992),检出限(S/N=3)为0.08 μg/L,定量限为(S/N=10)为0.2 μg/L,在0.2、1.0、2.0 μg/L 3个添加水平的克仑特罗回收率大于70.2%;相对标准偏差小于4.16%。方法分析速度快、灵敏度高、重现性好、试剂用量少、无基质干扰,可用于尿液中克仑特罗的检测。     

Metabolite profiling of colored rice (Oryza sativa L.) grains

HPLC analysis of dehulled red, black and non-colored indica and japonica rice subspecies revealed significant differences in the contents of the anthocyanins cyanidin-3-glucoside and peonidin-3-glucoside. The rice materials were subjected to a comparative capillary gas chromatography-based metabolite profiling approach. The employed extraction and fractionation protocol enables the analysis of a broad spectrum of lipophilic and hydrophilic low molecular weight constituents from different chemical classes. The method covers not only primary metabolites (e.g. sugars, fatty acids) but also nutritionally relevant constituents (e.g. α-tocopherol, γ-aminobutyric acid). Statistical assessment of the data via principal component analysis and agglomerative hierarchical clustering revealed a distinct grouping of the different colored rice subspecies on the basis of their metabolite profiles. Compared to non-colored and red rice, black rice exhibited, in particular, higher levels of fatty acid methyl esters, free fatty acids, organic acids and amino acids.     

Composition and biological activity of the essential oil from Thapsia minor, a new source of geranyl acetate

The essential oils from aerial parts of Thapsia minor Hoffmanns. & Link (Apiaceae), obtained by hydrodistillation, were analyzed by gas-chromatography and gas-chromatography-mass spectrometry. Oxygenated monoterpenes represented the main fraction with geranyl acetate (82.3-83.0%) as the major constituent, making this plant a good source of this compound.Biological activity of the essential oil was evaluated against several fungal strains. The highest activity was found against dermatophyte strains, Crytococcus neoformans and Candida guillermondii with minimal inhibitory concentrations values from 0.32 μl/ml to 1.25 μl/ml. The antifungal activity could be associated with the significant contribution of the oxygenated monoterpene geranyl acetate.Furthermore, this essential oil demonstrated to have potent anti-inflammatory in vitro activity, at concentrations that did not affect macrophages and keratinocytes viability, being the anti-inflammatory properties of the oil mainly due to geranyl acetate.These favorable results emphasize the antifungal and anti-inflammatory abilities of the molecule geranyl acetate and further support the exploitation of T. minor oil for pharmaceutical industry, in order to find new phytopharmaceuticals.     

单体香料芳樟醇的热裂解行为研究

[目的]研究单体香料芳樟醇的热裂解行为,为芳樟醇在卷烟加香中的应用提供参考依据.[方法]采用热裂解—气相色谱/质谱联用技术(Py-G-C/MS)分析芳樟醇在不同温度(300、400、500、600、700、800和900℃)下的热裂解行为,并根据主要热裂解产物及其相对含量的变化对芳樟醇热裂解机理进行初步探讨.[结果]热裂解温度低于500℃时,90.00%以上的芳樟醇未发生热裂解;热裂解温度升至600℃时,热裂解产物增多,主要是醇和烯等物质;热裂解温度升至900℃时,30.00%以上的芳樟醇发生热裂解.芳樟醇可裂解为香叶醇、二氢芳樟醇、月桂烯、罗勒烯、8-羟基芳樟醇、顺式氧化芳樟醇和反式氧化芳樟醇等香味物质.初步推导出芳樟醇按双键断裂重排、分子内脱水、双键加成及双键被氧化等4种方式进行热裂解.[结论]芳樟醇的热裂解产物以芳樟醇类物质为主,其自身的香气特征即代表热裂解后的香气特征,可添加到卷烟中以增加花香、木香和果香香气.     

高效液相色谱一电感耦合等离子体质谱联用技术测定海产品中5种形态砷

建立了海产品中5种形态砷（As）的高效液相色谱一电感耦合等离子体质谱联用测定方法。将样品冷冻干燥后采用矿（甲醇）：V（水）=3：1溶液,70℃水浴振摇30rain提取1次,再用y（甲醇）：y（水）=1：1溶液提取2次,提取液用阴离子交换柱分离,以20mmol·L-1碳酸铵[碳酸氢铵（NH。HCO,）＋氨基甲酸铵（NH：COONH。）]为流动相,用电感耦合等离子体质谱检测。5种As的检出限为0．057～0．13μg·L-1,定量限为0．19～0．43μg·kg。添加回收率为83．2％～115％,相对标准偏差小于10％。实际海产品样品测定结果表明,海产品中的As主要以砷甜菜碱和二甲基砷酸为主,5种形态As的和与总As相比,总体提取率达90％以上。     

海南单柄蛛毒素杀虫肽HNTXa的分离与性质分析

为了从海南单柄蛛Ornithoctonus hainana毒素中获得对哺乳动物无毒而对昆虫有毒杀作用的单一蛋白组分,应用反相层析和阳离子交换对海南单柄蛛粗毒素进行分离纯化。分别通过胸腔注射、腹腔注射和饲喂的方法测定各毒素组分对蟋蟀、小鼠和棉铃虫的毒性作用,并采用改进的寇式法计算LD50。分离得到一种新的杀虫肽,命名为海南单柄蛛毒素a(Hainana toxica,HNTXa),聚丙烯酰胺等点聚焦电泳(IEF-PAGE)分析其等电点为8.15～8.45。杀虫肽HNTXa对棉铃虫和蟋蟀有较强的抑制作用。棉铃虫经饲喂浸沾HNTXa的棉花叶片72h后,死亡率超过30%;HNTXa对蟋蟀的LD50值为58μg/g,LD50的95%置信区间为55～62μg/g;HNTXa对哺乳动物小鼠无明显毒性。     

脱除人参提取物中有机氯农药残留的亚临界丙烷萃取工艺研究

以人参为原料,研究了利用高效的亚临界丙烷萃取技术脱除人参提取物中残留的有机氯农药的可行性。就萃取压力、萃取温度、萃取时间和溶剂流量等对萃取效果的影响进行了比较,并用高压液相色谱仪测定了脱除农药前后人参皂甙的含量。结果表明,在萃取压力为8 MPa、65℃下萃取120 min,溶剂流量为2.94 kg/h的条件下,可几乎完全脱除γ-HCH,op-DDT,对TCNB、pp-DDT、DDE脱除率大于60%,人参皂甙损失小于6.53%。此方法为脱除人参中残留的有机氯农药提供了有效的途径。